Solid-state imaging devices are widely used in various fields as elementary elements for performing image input processing. Currently, solid-state imaging devices which are in general use are roughly classified as either CCD image sensors or CMOS image sensors. The principle of a CMOS image sensor is to amplify output of a photodiode functioning as a photo detector provided for each individual pixel by a MOS transistor and obtain the amplified output. The CMOS image sensors as small solid-state imaging devices driven with low power consumption are regarded as promising. In such a solid-state imaging device, each pixel is being made finer and finer and the number of pixels is being increased.
In a solid-state imaging device, specific color filters for respective pixels such as color filters of R (red), G (green), and B (blue) are provided. The solid-state imaging device generally adopts a color filter array called the Bayer array (see, for example, U.S. Pat. No. 3,971,065).
However, if binning processing (pixel addition) to increase sensitivity is performed on the Bayer array in a situation in which illuminance is low and sufficient sensitivity cannot be obtained from one pixel, the resolution may become lower or color reproducibility may worsen in an environment of low color temperature.